Researchers believe the gigantic pile of metal may have been deposited by a powerful asteroid strike.
The remains of the asteroid could be buried beneath the SouthPole-Aitken basin – a crater that measures approximately 1,553 miles across and eight miles deep.
Dr Peter James, a professor of planetary geophysics from Baylor University in Texas, said: “Imagine taking a pile of metal five times larger than the Big Island of Hawaii and burying it underground.
They found the force of gravity was affected by the gigantic mass, as it weighed the basin floor downward by more than half a mile.
Renowned conspiracy theorist Tyler Glockner has since posted a video offering his take on the find on YouTube channel secureteam10.
“Something is strange about this, something massive is buried underneath the moon.
“We know that it is a massive metallic structure and that the astronauts said the moon rang like a bell.
“We know about all the strange artificial structures on the moon’s surface so, with that, it’s a total mystery.
“One of many mysteries about our moon – there’s just something not right about our moon.”
More than 118,000 people have seen Tyler’s video since it was posted yesterday.
Another wrote: “Honestly, that is really strange.”
And a third commented: “That’s crazy how all this comes together.”
It comes just days after Tyler claimed to have found underground bases on Mars, using mapping software Google Earth.
And Professor Brian Cox recently revealed how “extraterrestrial life” could be hiding in a 900-mile-wide crater on the Red Planet.